Structure and Relative Stability of Si_n (n=10-16) Clusters

Ab initio molecular dynamics simulated annealing technique coupled with density functional theory in the local density approximation implemented in Spanish initiative for electronic simulations with thousands of atoms method is employed to search the ground state geometries of silicon clusters containing 10-16 atoms. We found a number of new isomers which are not previously reported. The atoms in all these clusters exhibit pronounced preference for residing on the surface. The binding energies increase while the highest occupied-lowest unoccupied molecular orbital gap generally decreases with the increase in clusters size.